| The coal mining are developing towards over1000m is an inevitable trend of mining industry in China. The thick coal mining is an important part of deep coal mining. The problem, which was exposed in deep mining with thick top-coal of Juye mining area, proposes higher demand to support these kinds of roadways in China.For the roof and two sides of deep roadway with thick top-coal are soft coal, its easy to apear large range of fratured zone; roof coal breaking and expanding seriously, easily separated from the basic roof; and the roof has large and lasting deformation, all of the above problems bring huge difficulty to control the surrounding rocks of roadway. At present, little study has been carried on for the defomiation failure and stability control mechanism of surrounding rock in deep roadways with thick top-coal. Among existing roadway support systems, economic and efficient support methods are deficient which suitable to these roadways. Therefore, fundamentally recognizing the deformation failure mechanism of surrounding rock in deep roadways with thick top-coal, and proposing reasonable support solution, is of important theoretical and practical meaning for deep and thick coal mining in China.Taking typical deep coal mine of Zhaolou in Juye mining area as engineering background, aiming at the difficult support of deep roadways with thick top-coal under high ground stress, methods of field measurement, theoretical analysis, material development, numerical analysis, model test and field test was combined to research deformation failure and control mechanism of surrounding rock in deep roadways with thick top-coal. Pressure relief anchor box beam (PRABB) support system that suitable for these roadways was therefore been developed. The main work and innovative points are list as follows:1. Field measurement study on deformation and destruction law of deep roadways with thick top-coal. Field monitor research was carried out on the engineering geological conditions of deep roadways with thick top-coal in Zhaolou mine, such as hydrologic geology, geostress and physical-mechanical properties of rock, as well as the mine pressure, the deformation and failure of surrounding rock, the stress state of support units under conditions of original supporting program. The main reason and mechanism were obtained from these researches and analysis, which of serious bulking deformation, great bed separation amount and uncontrollable lasting deformation on the roof and surrounding rock of deep roadways with thick top-coal in Zhaolou coal mine.2. Mechanism research on roof carving in deep roadways with thick top-coal. Based on the limit analysis theory, adopted generalized Hoek-Brown experience strength rule, and considered the effect of strain level and support load of roof and surrounding rock in roadways, the roof carving trace equation was deduced. Meanwhile, the effect to the range of roof carving was discussed, which caused by mechanic parameters of different rocks, strain level of surrounding rocks and support load. Calculation example analysis was carried out on the deep rectangular roadways with thick top-coal in3302work face of Zhaolou coal mine, and the effect to the range of roof carving which caused by support load has been researched. Meanwhile, engineering technology measure has also been put forward according to the engineering practice.3. The research and development of pressure relief anchor box beam(PRABB) support system. The support concept of high strength coupling pressure relief was put forward, which is first anti-pressure, second pressure relief, and third anti-pressure. The PRABB support system was developed, which has high strength support pressure, better bending stiffness, lower pre-tightening force loss, quantitative pressure relief, good supporting surface effect and reasonable economic. Fourteen test schemes with different arrange modes were designed, classifying into four kinds of PRABB support system, I-steel anchor beams support system, T-steel strip anchor beams support system and U-steel anchor beams support system.4. The evaluation index research on the contrast of support systems. In the research, four indexes were proposed, which of roadway characterization deformation D, the economic index of surrounding rock control I, the whole performance utilization ratio of support system combined units η and the combined units coupling ratio of support system W. By the use of hierarchy analytical method, the deformation weight value of surrounding rock in roadways and coupling ratio weight value of support system combined units were determined. The above indexes were used in the contrastive evaluation of the combined components coupling performance of support system and roadway support effect, and therefore the contrastive evaluation can be quantification.5. Numerical research on coupling performance of support members. Thirteen contrastive schemes were designed with different combination of support members and pre-stressing. By means of the statistical analysis of numerical test on these schemes, contrastive research was carried out on the coupling performance of each scheme. Results show that the top three schemes with best coupling effect are scheme N3(Ⅱ12b+(?)22anchor), scheme N2(Ⅱ12a+(?)17.8anchor) and scheme N5(Ⅱ12c+(?)22anchor). Meanwhile, the two factors of anchor type and pre-pressure were analized, which has affected coupling performance and support effect of the support systems.6. Contrastive analysis of support effect numerical test. As the support effect analysis of the numerical test on the fourteen support schemes show, the support effect of PRABB support scheme was dramatically enhanced than by original scheme; the PRABB support system has advantage than I-steel anchor beams support system on the support effect and economic; among the four support scheme of PRABB, cross and longitudinal combination scheme was best in surrounding rock controlling, longitudinal single anchor beam scheme was lest best, and then longitudinal double anchor beam scheme, cross anchor beam program was relatively poor.7. The field application of new monitoring methods and evaluation system of field support components. Force-measuring box beam, force-measuring I-steel beam and force-measuring steel strip were developed and applied in the field test, to monitor the force on the support components. By use of the established evaluation system, integrating contrastive analysis has been carried out on the monitoring results of surrounding rock convergence, roof abscission layer, bending settlementof roof, deep displacement of surrounding rock, anchor rod acting force, the force on the pad of anchor, steel beam steel strip acting force in the field test and make quantitative comprehensive evaluation of the superiority and inferiority of different schemes.8. Contrastive research field test with multi-schemes. Considered the characteristic of3302working face crosshead, combining with theoretical analysis and numerical test results, the choosing rule of support scheme was put forward, which guided the field test research of eleven schemes classified into three kinds. Many monitoring station were set up on the test section for each support scheme, the conclusion which obtained from the integrating contrastive analysis on monitoring result was almost the same with the theoretical analysis and numerical test. All schemes with PRABB were better than I-steel scheme, and had dramatically advantage than original support scheme. Among the schemes of PRABB, longitudinal and cross combination scheme has the best effect, longitudinal single anchor beam scheme been lest best. Meanwhile, the engineering advices after integrative analysis was proposed, which is foist choose longitudinal and cross combination scheme of PRABB under harsh geological conditions, and choosing longitudinal single anchor beam scheme when the geological conditions is better.9. Develop of flexible load system. Considering the existing load boundary condition problems of geomechanics model test, based on the research of various kinds of special flexible rubber materials, combined the test requirement, the new flexible uniform distributed pressure load device was developed and used in the model test, which was better stimulate original condition more actual.10. Contrastive research of geomechanics model test. Based on the engineering geological condition of deep roadways with thick top-coal in Zhaolou coal mine, the geomechanics model test research was carried out on the excavation and support process of3302wording face crossheading. Advanced monitoring methods were adopted which include fiber grating and resistance strain test system, grating multi-point extensometer measurement and data collection system, digital photography system and new force monitoring system of support component. Meanwhile, the strain evolution law of surrounding rocks with different support schemes, surrounding rocks deformation law and the force character of support units were obtained. The test results show that longitudinal single beam scheme has better support effect than cross beam scheme, which is consistent with field rule.11. Function mechanism research of anchor beams support system.3D mechanics model was set up, which simulate the anchor beams support system acting on roof and surrounding rocks. From theoretical analysis and derivation, the confining pressure calculation formula of roof and surrounding rocks was obtained, which is according to different arrangement modes of anchor beams, cables and anchors act alone or combined. By means of the formula, analysis of examples on the strain statement of roof and surrounding rocks in different arrangement modes of anchor beams support system, the result shows that:the confining pressure statement caused by cross and longitudinal combination scheme was the best, longitudinal single beam scheme was lest better, longitudinal double beams scheme and cross beam scheme were relatively poor. From the integrative and contrastive analysis of the results obtained from theoretical calculation, numerical test and field test, function mechanism of anchor beams support system was obtained.
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